The Germans were five goals up within 29 minutes of the match and went on to record the biggest win by any team in the semi-final of the World Cup.
"It's the best result of my career when you consider the importance of the game. I could not believe it," he told FIFA.com.
"It was crazy to watch us score five goals so early. Everything went so fluently. We played through their lines, found always a player who was completely free in front of the goal. We showed some great skills, some great passing moves. It was nice to watch."
Germany will face Argentina in the final at the Maracana on Sunday.